mptcp: add rm_list_rx in mptcp_pm_data

This patch added a new member rm_list_rx for struct mptcp_pm_data as an
list of the removing address ids on the incoming direction. Initialized
its nr field to zero in mptcp_pm_data_init.

In mptcp_pm_rm_addr_received, set it as the input rm_list.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index d7daf7e..82a63ab 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -208,6 +208,7 @@ struct mptcp_pm_data {
 	u8		subflows;
 	u8		status;
 	struct mptcp_rm_list rm_list_tx;
+	struct mptcp_rm_list rm_list_rx;
 	u8		rm_id;
 };